package main

import (
	"fmt"
	"io"
	"os"
	"strings"
)

func main() {
	src := strings.NewReader("Happy New Year")
	dst := new(strings.Builder)
	written, err := io.CopyN(dst, src, 5)
	if err != nil {
		fmt.Fprintf(os.Stderr, "ERROR: %v\n", err)
	}
	fmt.Println(written, dst.String())
}
